Introduction
Some of the energy that powers our homes comes from WIND. Wind energy is a clean, unlimited, renewable source of energy that many of us take for granted. In fact, most of us only really notice the wind when it becomes unusually strong. Can you think back to day that was particularly windy? What was it like? A big layer of air called the atmosphere surrounds the Earth. The air within this layer moves from place to place when it warms up or cools down. This moving air is known as wind. Winds move moisture and heat around the world and also produce much of our weather. Before we learn about wind, we need to learn a little bit about our atmosphere.
Atmosphere Composition
The atmosphere is composed of a mix of several different gases in differing amounts. The permanent gases whose percentages do not change from day to day are nitrogen, oxygen and argon. Nitrogen accounts for 78% of the atmosphere, oxygen 21% and argon 0.9%. Gases like carbon dioxide, nitrous oxides, methane, and ozone are trace gases that account for about a tenth of one percent of the atmosphere. Water vapor is unique in that its concentration varies from 0-4% of the atmosphere depending on where you are and what time of the day it is. In the cold, dry arctic regions water vapor usually accounts for less than 1% of the atmosphere, while in humid, tropical regions water vapor can account for almost 4% of the atmosphere. Water vapor content is very important in predicting weather. To summarize, the following gases makeup our atmosphere:
Nitrogen – 78 percent
Oxygen – 21 percent
Argon – 0.93 percent
Carbon dioxide – 0.038 percent
Atmosphere Layers
Earth's atmosphere is divided into four to five main layers, the troposphere, the stratosphere, the mesosphere, the thermosphere, and depending upon who you ask, the exosphere. The atmosphere thins out in each higher layer until the gases dissipate in space. There is no distinct boundary between the atmosphere and space, but an imaginary line about 68 miles (110 kilometers) from the surface, called the Karman line, is usually where scientists say atmosphere meets outer space.
The troposphere is the layer closest to Earth's surface. It is 4 to 12 miles (7 to 20 km) thick and contains half of Earth's atmosphere. Air is warmer near the ground and gets colder higher up. Nearly all of the water vapor and dust in the atmosphere are in this layer and that is why clouds, weather, and much of our WIND occurs in this layer.
The stratosphere is the second layer. It starts above the troposphere and ends about 31 miles (50 km) above ground. Ozone is abundant here and it heats the atmosphere while also absorbing harmful radiation from the sun. The air here is very dry, and it is about a thousand times thinner here than it is at sea level. Because of that, this is where jet aircraft and weather balloons fly.
The mesosphere starts at 31 miles (50 km) and extends to 53 miles (85 km) high. The top of the mesosphere
, called the mesopause, is the coldest part of Earth's atmosphere with temperatures averaging about minus 130 degrees F (minus 90 C). This layer is hard to study. Jets and balloons don't go high enough, and satellites and space shuttles orbit too high. Scientists do know that meteors burn up in this layer.
The thermosphere extends from about 56 miles (90 km) to between 310 and 620 miles (500 and 1,000 km). Temperatures can get up to 2,700 degrees F (1,500 C) at this altitude. The thermosphere is considered part of Earth's atmosphere, but air density is so low that most of this layer is what is normally thought of as outer space. In fact, this is where the space shuttles flew and where the International Space Station orbits Earth. This is also the layer where the auroras occur. Charged particles from space collide with atoms and molecules in the thermosphere, exciting them into higher states of energy. The atoms shed this excess energy by emitting photons of light, which we see as the colorful Aurora Borealis and Aurora Australis.
Depending upon which scientist you ask, some even include a fifth layer of the atmosphere. The exosphere, the highest layer, is extremely thin and is where the atmosphere merges into outer space. It is composed of very widely dispersed particles of hydrogen and helium.
Heat Transfer
Simply put, wind is the movement of air. Air moves because of temperature differences throughout Earth's surface. If the land is heated, how do you think this affects the air above it? Because water and land absorb heat differently, this affects the air above it, creating regions of high pressure (sinking air) and low pressure (rising air); and Wind flow from areas of high pressure to low pressure. Heat plays a major role in the movement of air, or wind. So, in order for us to understand wind, we must first learn about basic principles about heat and heat transfer. Heat is the energy that flows from an object with a higher temperature to an object with a lower temperature. Heat is transferred by two ways: CONDUCTION and CONVECTION.
Convection is the transfer of heat that occurs when molecules bump into one another. An example would be a hot pan on the stove; as the hot pan heats up, the molecules begin to vibrate faster bumping into the colder surrounding molecules, as a result heat is transferred!!!
Conduction occurs by the flow of a heated material and only occurs with gasses and liquids. AN example would be a hot pot of water on a stove. As the water begins to heat up the molecules expand, becoming lighter and therefore rises to the surface. As the hot water rises the colder heavier water fills in. Eventually a current begins develop transferring heat throughout the pot of water. We call these currents convection currents.
Daily Winds
Land and water absorb heat differently. Land heats up and cools down faster than water, creating small areas of low pressure (rising air) and high pressure (sinking air). This uneven heating creates Sea and Land breezes. Sea and Land breezes is an example of heat transfer by convection! Remember,Convection is one of the major ways that heat is transferred. It occurs because hotter liquids and gasses have a tendency to rise, while colder liquids and gasses have a tendency to sink.
Seabreezes
A Seabreeze occurs during the day and is a gust of wind that forms as a result of the uneven heating between land and water; WIND moves from water to land. Throughout the morning, the sun rises and warms the land. The surface of the land becomes warmer relative to the surface of the ocean. By the afternoon warm air over the land begins to rise upward, while cooler heavier air over the ocean moves over the land creating a sea breeze. A sea breeze develops during the day due to uneven heating of land and water; as a result wind flows from ocean on to land. A Seabreeze is an example of heat transfer by Convection! In this case, wind is flowing from ocean to land, transferring heat.
Landbreezes
A Landbreeze occurs at night and is a gust of wind that forms as a result of the uneven heating between land and water; WIND moves from land to water. In the evening, the sun goes down and the land begins to cool down. The surface of the land is now cooler relative to the surface of the ocean. By midnight, warm air over the ocean begins to rise upward while cooler, heavier air over the land moves out to sea; creating a landbreeze. A landbreeze develops at night due to the uneven heating of land and water; as a result wind flows from land to ocean.
A Landbreeze is an example of heat transfer by Convection! In this case, wind is flowing from land to ocean, transferring heat.
Uneven Heating of the Earth Click on Step 1. The Earth is heated unevenly by the Sun. Locations near the Earth’s equator receive direct high angle sunlight creating warm surface /air temperatures. This is why tropical areas around the equator are relatively warm and hot year round; it has nothing to do with the equator being closer to the Sun. It is really about the degree and intensity of sunlight striking the Earth.
Click on Step 2. As you move farther from the equator, sunlight becomes more spread out and weaker creating slightly cooler surface/air temperatures.
Click on Step 3. Because the earth is round, sunlight near the poles is even more spread out over an even larger area, creating cold air temperatures.
Click on Step 4. As a result, the Earth is heated unevenly--warm temperatures along the equator, and cold temperatures near the poles. Remember, heat flows from warmer areas to colder areas by convection.
Click on Step 5. The uneven heating of earth creates a temperature imbalance, moving warm air from equatorial regions to cold polar regions by convection. This simplistic convection current begins when hot air rises at the equator and cold air sinks at the poles--thus creating our wind! Think of this convection current as Earth’s Heating and Air Conditioning Unit. Without this heat distribution, the Polar regions would be 10 degrees colder and the equatorial regions would be 10 degrees hotter!
Coriolis Effect
Ever wonder why the water spirals down your drain in clockwise fashion? The reason why water, wind, and any other free-moving objects appear to curve or spiral is due to the Coriolis Effect. The Coriolis effect is the the apparent "curve" or deflection of all free moving objects (such as airplanes, wind, missiles, and ocean currents) moving in a straight path relative to the earth’s surface. Wind is just one of many of these free moving objects. Hurricanes, and tornado all spiral clockwise in the northern hemisphere. Typhoons (hurricane in the southern hemisphere) spiral in a counter clockwise motion.
Global Winds
For hundreds of years, sailors have used the global winds to navigate the Earth’s Oceans. These global winds, such as the Westerlies and Tradewinds are a
steady continual wind that exist at different latitudes. If you combine the Coriolis Effect with the uneven heating of earth, a global wind pattern begins to emerge and take shape. These Global Winds are the dominant prevailing wind patterns that blow in a fairly constant, steady direction across our earth Global Wind Patterns are important because they distribute and circulate heat from the equatorial regions to the polar regions by convection. Think of these winds as the earth's heating and air conditioning system. Notice these winds become deflected and appear to "curve" as a result of the Coriolis Effect.
At the Equator the first wind system can be found called the Tradewinds. Tradewinds are Winds that blow from east to west between 0 and 30 degrees north and south latitude. Moving farther from the equator you get the Westerlies. The Westerlies are Winds that blow from west to east between 30 and 60 degrees north and south latitude. Moving even farther from the equator, and all the way up to the Polar Regions are the Easterlies. The Easterlies are Winds that blow from east to west between 60 and 90 degrees north and south latitude.
ARTICLE: Wind Energy -- Good or Bad for America? Wind energy capacity is growing rapidly all over the world. The countries want more renewable energy to replace fossil fuels, and wind is certainly one of the most interesting renewable energy options to achieve this goal. When we think of wind power, we generally think of those large, high tech towers with slowly spinning blades that have sprung up in the past decade on hilltops in many areas of the country. But the fact is, wind is one of the oldest sources of power used by man. Our ancient ancestors used the wind to propel boats, grind grain and pump water. Ancient mariners used sails to capture the wind and explore the world. Farmers once used windmills to grind their grains and pump water. Today, more and more people are using wind turbines to wring electricity from the breeze. Over the past decade, wind turbine use has increased at more than 25 percent a year. Still, it only provides a small fraction of the world's energy.
Wind is the movement of air from an area of high pressure to an area of low pressure. In fact, wind exists because the sun unevenly heats the surface of the Earth. As hot air rises, cooler air moves in to fill the void. As long as the sun shines, the wind will blow. And as long as the wind blows, people will harness it to power their lives. While all of these applications still exist today, wind power is now primarily used to generate electricity at both the large and the small scale. Our discussion today will focus on large utility scale installations. In all cases, it is the kinetic energy, or movement of the air, that provides the mechanical power to perform the various forms of work.
According to a recent report posted by the DOE’s National Renewable Energy Lab (NREL), clean renewable energy sources like wind can contribute 80% of American electricity by the year 2050. Much of it will be provided by wind power installations of this type.
Wind power has some obvious advantages: it’s clean (doesn’t pollute our air) and renewable (doesn’t run out) and relatively cheap. While these advantages are largely global in nature (e.g. reduced greenhouse gas emissions and fossil fuel depletion), the disadvantages are primarily local (e.g. land use, noise and visual pollution). Of course, the main disadvantage of wind power is that the wind does not blow consistently or steadily.
Other issues have been raised, which have often been. For example, one criticism is that windmills kill lots of wild birds. This was true of the early windmills, especially in the case of the wind farm located near Altamont Pass in California. Those turbines spun at high speeds and were located near a major avian thoroughfare. Today’s high efficiency turbines spin at lower speeds and use smooth poles to support the turbine instead of the lattice-style structures used earlier – which actually made nice bird nesting grounds.
Today, even the Audubon Bird Society supports wind power, recognizing that global warming causing a far greater threat to the long term viability of bird populations than the occasional collision of a bird with a tower. The number of annual bird fatalities (around 20,000) is tiny when compared to transmission lines or cats.
Most wind energy comes from turbines that can be as tall as a 20-story building and have three 200-foot-long (60-meter-long) blades. These contraptions look like giant airplane propellers on a stick. The wind spins the blades, which turn a shaft connected to a generator that produces electricity. Other turbines work the same way, but the turbine is on a vertical axis and the blades look like a giant egg beater.
The biggest wind turbines generate enough electricity to supply about 600 U.S. homes. Wind farms have tens and sometimes hundreds of these turbines lined up together in particularly windy spots, like along a ridge. Smaller turbines erected in a backyard can produce enough electricity for a single home or small business.
Another benefit to wind energy is more jobs and employment for U.S. workers. In 2011, approximately 670,000 people were employed directly or indirectly in the global wind power industry. According to an Energy [R]evolution 2012 report, wind energy would employ 1.7 million people by 2030. Jobs range from manufacturing to services and development. There is currently a shortage of skilled workers and engineers in the wind business.
By 2020, more than 520,000 people will be employed by wind energy. By 2030, the figure will be 794,079, with 62 percent of wind jobs in the offshore sector.
Wind is a clean source of renewable energy that produces no air or water pollution. And since the wind is free, operational costs are nearly zero once a turbine is erected. Mass production and technology advances are making turbines cheaper, and many governments offer tax incentives to spur wind-energy development. Some people think wind turbines are ugly and complain about the noise the machines make. The slowly rotating blades can also kill birds and bats, but not nearly as many as cars, power lines, and high-rise buildings do. The wind is also variable: If it's not blowing, there's no electricity generated.
Nevertheless, the wind energy industry is booming. Globally, generation more than quadrupled between 2000 and 2006. At the end of last year, global capacity was more than 70,000 megawatts. In the energy-hungry United States, a single megawatt is enough electricity to power about 250 homes. Germany has the most installed wind energy capacity, followed by Spain, the United States, India, and Denmark. Development is also fast growing in France and China. Industry experts predict that if this pace of growth continues, by 2050 the answer to one third of the world's electricity needs will be found blowing in the wind.
Here then are the wind power pros and cons. Pros
Clean energy, no fuel to drill, frack, mine, transport or burn
Renewable and sustainable
Costs are relatively low and continue to decrease
Abundant domestic supply (16X current electric demand!)
The power is essentially free once the infrastructure is paid for.
Low life cycle carbon footprint (Does not release carbon dioxide and other greenhouse gases that contribute to climate change)
Can be used almost anywhere.
Creates a steady demand for jobs, and this demand is expected to grow
Cons
As mentioned earlier, the wind is inconsistent, unsteady and unpredictable
Wind power is not cheap and like many energy sources, rely on government subsidies to remain competitive.
Wind farms are generally located in rural areas that might be otherwise picturesque and cause visual pollution.. They are considered by some people to be an eyesore.
Some people complain of noise from the turbines.
Wildlife impact. Not only birds, but bats have experienced fatalities.
Localized impact on night-time temperatures and weather
At the end of 2011, the US had 46,919MW of installed wind capacity. This number is expected to grow rapidly, whether or not production tax credits (PTC) are renewed. There have been a number of recent mergers among wind developers as the industry consolidates. In summary, wind power, is not a perfect solution, but it is far better than just about anything else we have available at the moment. I would consider it a good long term transitional energy source over the next fifty to a hundred years. The other good thing about wind: unlike nuclear power, or tar sands oil, which will each leave a long term toxic legacy, when we are finally done with wind, we can simply take down the towers and allow nature to grow back in.
ARTICLE: Turning WIND into ELECTRICITY
The process of wind-produced electrical generation begins when the force of the wind pushes against the turbines’ blades, causing them to rotate, creating mechanical energy. Wind turbines operate on a simple principle. The energy in the wind turns two or three propeller-like blades around a rotor. The rotor is connected to the main shaft, which spins a generator to create electricity. Wind turbines are mounted on a tower to capture the most energy. At 100 feet (30 meters) or more above ground, they can take advantage of faster and less turbulent wind. Wind turbines can be used to produce electricity for a single home or building, or they can be connected to an electricity grid (shown here) for more widespread electricity distribution.
The spinning blades, attached to a hub and a low-speed shaft, turn along with the blades. The rotating low-speed shaft is connected to a gearbox that connects to a high-speed shaft on the opposite side of the gearbox. This high-speed shaft connects to an electrical generator that converts the mechanical energy from the rotation of the blades into electric energy. Spinning between 11 and 20 times per minute, each turbine can generate a maximum 1.5 megawatts of electricity -- enough to power, on average, more than 500 residential homes
Project WIND Discussion Forum You are just about done with your project. But first you need to visit the online discussion forum and thoroughly answer one of the questions below in detail citing evidence. Remember, these questions should not be difficult because you have already done research. When you are finished, you are required to read and grade each response from every person in your lab group. Use the rubric below to guide you through the grading process. Remeber to make a claim and support that claim with evidence from the readings and research.
Is Wind Energy Good or Bad for AMERICA?
FULL CREDIT
PARTIAL CREDIT
NO CREDIT
10 POINTS awarded if there are 8-10 complete sentences that answer one of the required questions above with correct spelling, punctuation, & grammar
5 POINTS awarded if there are 4-7 complete sentences that answer one of the required questions above with mostly correct spelling, punctuation, and grammar
0 POINTS awarded if there are 0-3 complete sentences that answer one of the required questions above
10 POINTS awarded if at least 4 sources of evidence were cited from the research and readings.
5 POINTS awarded if 2-3 sources of evidence were cited from the research and readings.
0 POINTS awarded if 0-1 sources of evidence were cited from the research and readings.
Some of the energy that powers our homes comes from WIND. Wind energy is a clean, unlimited, renewable source of energy that many of us take for granted. In fact, most of us only really notice the wind when it becomes unusually strong. Can you think back to day that was particularly windy? What was it like? A big layer of air called the atmosphere surrounds the Earth. The air within this layer moves from place to place when it warms up or cools down. This moving air is known as wind. Winds move moisture and heat around the world and also produce much of our weather. Before we learn about wind, we need to learn a little bit about our atmosphere.
Atmosphere Composition
The atmosphere is composed of a mix of several different gases in differing amounts. The permanent gases whose percentages do not change from day to day are nitrogen, oxygen and argon. Nitrogen accounts for 78% of the atmosphere, oxygen 21% and argon 0.9%. Gases like carbon dioxide, nitrous oxides, methane, and ozone are trace gases that account for about a tenth of one percent of the atmosphere. Water vapor is unique in that its concentration varies from 0-4% of the atmosphere depending on where you are and what time of the day it is. In the cold, dry arctic regions water vapor usually accounts for less than 1% of the atmosphere, while in humid, tropical regions water vapor can account for almost 4% of the atmosphere. Water vapor content is very important in predicting weather. To summarize, the following gases makeup our atmosphere:
Atmosphere LayersEarth's atmosphere is divided into four to five main layers, the troposphere, the stratosphere, the mesosphere, the thermosphere, and depending upon who you ask, the exosphere. The atmosphere thins out in each higher layer until the gases dissipate in space. There is no distinct boundary between the atmosphere and space, but an imaginary line about 68 miles (110 kilometers) from the surface, called the Karman line, is usually where scientists say atmosphere meets outer space.
The troposphere is the layer closest to Earth's surface. It is 4 to 12 miles (7 to 20 km) thick and contains half of Earth's atmosphere. Air is warmer near the ground and gets colder higher up. Nearly all of the water vapor and dust in the atmosphere are in this layer and that is why clouds, weather, and much of our WIND occurs in this layer.
The stratosphere is the second layer. It starts above the troposphere and ends about 31 miles (50 km) above ground. Ozone is abundant here and it heats the atmosphere while also absorbing harmful radiation from the sun. The air here is very dry, and it is about a thousand times thinner here than it is at sea level. Because of that, this is where jet aircraft and weather balloons fly.
The mesosphere starts at 31 miles (50 km) and extends to 53 miles (85 km) high. The top of the mesosphere
, called the mesopause, is the coldest part of Earth's atmosphere with temperatures averaging about minus 130 degrees F (minus 90 C). This layer is hard to study. Jets and balloons don't go high enough, and satellites and space shuttles orbit too high. Scientists do know that meteors burn up in this layer.
The thermosphere extends from about 56 miles (90 km) to between 310 and 620 miles (500 and 1,000 km). Temperatures can get up to 2,700 degrees F (1,500 C) at this altitude. The thermosphere is considered part of Earth's atmosphere, but air density is so low that most of this layer is what is normally thought of as outer space. In fact, this is where the space shuttles flew and where the International Space Station orbits Earth. This is also the layer where the auroras occur. Charged particles from space collide with atoms and molecules in the thermosphere, exciting them into higher states of energy. The atoms shed this excess energy by emitting photons of light, which we see as the colorful Aurora Borealis and Aurora Australis.
Depending upon which scientist you ask, some even include a fifth layer of the atmosphere. The exosphere, the highest layer, is extremely thin and is where the atmosphere merges into outer space. It is composed of very widely dispersed particles of hydrogen and helium.
Heat Transfer
Simply put, wind is the movement of air. Air moves because of temperature differences throughout Earth's surface. If the land is heated, how do you think this affects the air above it? Because water and land absorb heat differently, this affects the air above it, creating regions of high pressure (sinking air) and low pressure (rising air); and Wind flow from areas of high pressure to low pressure. Heat plays a major role in the movement of air, or wind. So, in order for us to understand wind, we must first learn about basic principles about heat and heat transfer. Heat is the energy that flows from an object with a higher temperature to an object with a lower temperature. Heat is transferred by two ways: CONDUCTION and CONVECTION.
Convection is the transfer of heat that occurs when molecules bump into one another. An example would be a hot pan on the stove; as the hot pan heats up, the molecules begin to vibrate faster bumping into the colder surrounding molecules, as a result heat is transferred!!!
Conduction occurs by the flow of a heated material and only occurs with gasses and liquids. AN example would be a hot pot of water on a stove. As the water begins to heat up the molecules expand, becoming lighter and therefore rises to the surface. As the hot water rises the colder heavier water fills in. Eventually a current begins develop transferring heat throughout the pot of water. We call these currents convection currents.
Daily Winds
Land and water absorb heat differently. Land heats up and cools down faster than water, creating small areas of low pressure (rising air) and high pressure (sinking air). This uneven heating creates Sea and Land breezes. Sea and Land breezes is an example of heat transfer by convection! Remember,Convection is one of the major ways that heat is transferred. It occurs because hotter liquids and gasses have a tendency to rise, while colder liquids and gasses have a tendency to sink.
Seabreezes
A Seabreeze occurs during the day and is a gust of wind that forms as a result of the uneven heating between land and water; WIND moves from water to land. Throughout the morning, the sun rises and warms the land. The surface of the land becomes warmer relative to the surface of the ocean. By the afternoon warm air over the land begins to rise upward, while cooler heavier air over the ocean moves over the land creating a sea breeze. A sea breeze develops during the day due to uneven heating of land and water; as a result wind flows from ocean on to land. A Seabreeze is an example of heat transfer by Convection! In this case, wind is flowing from ocean to land, transferring heat.
Landbreezes
A Landbreeze occurs at night and is a gust of wind that forms as a result of the uneven heating between land and water; WIND moves from land to water. In the evening, the sun goes down and the land begins to cool down. The surface of the land is now cooler relative to the surface of the ocean. By midnight, warm air over the ocean begins to rise upward while cooler, heavier air over the land moves out to sea; creating a landbreeze. A landbreeze develops at night due to the uneven heating of land and water; as a result wind flows from land to ocean.
A Landbreeze is an example of heat transfer by Convection! In this case, wind is flowing from land to ocean, transferring heat.
Uneven Heating of the Earth
Click on Step 1. The Earth is heated unevenly by the Sun. Locations near the Earth’s equator receive direct high angle sunlight creating warm surface /air temperatures. This is why tropical areas around the equator are relatively warm and hot year round; it has nothing to do with the equator being closer to the Sun. It is really about the degree and intensity of sunlight striking the Earth.
Click on Step 2. As you move farther from the equator, sunlight becomes more spread out and weaker creating slightly cooler surface/air temperatures.
Click on Step 3. Because the earth is round, sunlight near the poles is even more spread out over an even larger area, creating cold air temperatures.
Click on Step 4. As a result, the Earth is heated unevenly--warm temperatures along the equator, and cold temperatures near the poles. Remember, heat flows from warmer areas to colder areas by convection.
Click on Step 5. The uneven heating of earth creates a temperature imbalance, moving warm air from equatorial regions to cold polar regions by convection. This simplistic convection current begins when hot air rises at the equator and cold air sinks at the poles--thus creating our wind! Think of this convection current as Earth’s Heating and Air Conditioning Unit. Without this heat distribution, the Polar regions would be 10 degrees colder and the equatorial regions would be 10 degrees hotter!
Coriolis Effect
Ever wonder why the water spirals down your drain in clockwise fashion? The reason why water, wind, and any other free-moving objects appear to curve or spiral is due to the Coriolis Effect. The Coriolis effect is the the apparent "curve" or deflection of all free moving objects (such as airplanes, wind, missiles, and ocean currents) moving in a straight path relative to the earth’s surface. Wind is just one of many of these free moving objects. Hurricanes, and tornado all spiral clockwise in the northern hemisphere. Typhoons (hurricane in the southern hemisphere) spiral in a counter clockwise motion.
Global Winds
For hundreds of years, sailors have used the global winds to navigate the Earth’s Oceans. These global winds, such as the Westerlies and Tradewinds are a
steady continual wind that exist at different latitudes. If you combine the Coriolis Effect with the uneven heating of earth, a global wind pattern begins to emerge and take shape. These Global Winds are the dominant prevailing wind patterns that blow in a fairly constant, steady direction across our earth Global Wind Patterns are important because they distribute and circulate heat from the equatorial regions to the polar regions by convection. Think of these winds as the earth's heating and air conditioning system. Notice these winds become deflected and appear to "curve" as a result of the Coriolis Effect.
At the Equator the first wind system can be found called the Tradewinds. Tradewinds are Winds that blow from east to west between 0 and 30 degrees north and south latitude. Moving farther from the equator you get the Westerlies. The Westerlies are Winds that blow from west to east between 30 and 60 degrees north and south latitude. Moving even farther from the equator, and all the way up to the Polar Regions are the Easterlies. The Easterlies are Winds that blow from east to west between 60 and 90 degrees north and south latitude.
ARTICLE: Wind Energy -- Good or Bad for America?
Wind energy capacity is growing rapidly all over the world. The countries want more renewable energy to replace fossil fuels, and wind is certainly one of the most interesting renewable energy options to achieve this goal. When we think of wind power, we generally think of those large, high tech towers with slowly spinning blades that have sprung up in the past decade on hilltops in many areas of the country. But the fact is, wind is one of the oldest sources of power used by man. Our ancient ancestors used the wind to propel boats, grind grain and pump water. Ancient mariners used sails to capture the wind and explore the world. Farmers once used windmills to grind their grains and pump water. Today, more and more people are using wind turbines to wring electricity from the breeze. Over the past decade, wind turbine use has increased at more than 25 percent a year. Still, it only provides a small fraction of the world's energy.
Wind is the movement of air from an area of high pressure to an area of low pressure. In fact, wind exists because the sun unevenly heats the surface of the Earth. As hot air rises, cooler air moves in to fill the void. As long as the sun shines, the wind will blow. And as long as the wind blows, people will harness it to power their lives.
While all of these applications still exist today, wind power is now primarily used to generate electricity at both the large and the small scale. Our discussion today will focus on large utility scale installations. In all cases, it is the kinetic energy, or movement of the air, that provides the mechanical power to perform the various forms of work.
According to a recent report posted by the DOE’s National Renewable Energy Lab (NREL), clean renewable energy sources like wind can contribute 80% of American electricity by the year 2050. Much of it will be provided by wind power installations of this type.
Wind power has some obvious advantages: it’s clean (doesn’t pollute our air) and renewable (doesn’t run out) and relatively cheap. While these advantages are largely global in nature (e.g. reduced greenhouse gas emissions and fossil fuel depletion), the disadvantages are primarily local (e.g. land use, noise and visual pollution). Of course, the main disadvantage of wind power is that the wind does not blow consistently or steadily.
Other issues have been raised, which have often been. For example, one criticism is that windmills kill lots of wild birds. This was true of the early windmills, especially in the case of the wind farm located near Altamont Pass in California. Those turbines spun at high speeds and were located near a major avian thoroughfare. Today’s high efficiency turbines spin at lower speeds and use smooth poles to support the turbine instead of the lattice-style structures used earlier – which actually made nice bird nesting grounds.
Today, even the Audubon Bird Society supports wind power, recognizing that global warming causing a far greater threat to the long term viability of bird populations than the occasional collision of a bird with a tower. The number of annual bird fatalities (around 20,000) is tiny when compared to transmission lines or cats.
Most wind energy comes from turbines that can be as tall as a 20-story building and have three 200-foot-long (60-meter-long) blades. These contraptions look like giant airplane propellers on a stick. The wind spins the blades, which turn a shaft connected to a generator that produces electricity. Other turbines work the same way, but the turbine is on a vertical axis and the blades look like a giant egg beater.
The biggest wind turbines generate enough electricity to supply about 600 U.S. homes. Wind farms have tens and sometimes hundreds of these turbines lined up together in particularly windy spots, like along a ridge. Smaller turbines erected in a backyard can produce enough electricity for a single home or small business.
Another benefit to wind energy is more jobs and employment for U.S. workers. In 2011, approximately 670,000 people were employed directly or indirectly in the global wind power industry. According to an Energy [R]evolution 2012 report, wind energy would employ 1.7 million people by 2030. Jobs range from manufacturing to services and development. There is currently a shortage of skilled workers and engineers in the wind business.
By 2020, more than 520,000 people will be employed by wind energy. By 2030, the figure will be 794,079, with 62 percent of wind jobs in the offshore sector.
Wind is a clean source of renewable energy that produces no air or water pollution. And since the wind is free, operational costs are nearly zero once a turbine is erected. Mass production and technology advances are making turbines cheaper, and many governments offer tax incentives to spur wind-energy development. Some people think wind turbines are ugly and complain about the noise the machines make. The slowly rotating blades can also kill birds and bats, but not nearly as many as cars, power lines, and high-rise buildings do. The wind is also variable: If it's not blowing, there's no electricity generated.
Nevertheless, the wind energy industry is booming. Globally, generation more than quadrupled between 2000 and 2006. At the end of last year, global capacity was more than 70,000 megawatts. In the energy-hungry United States, a single megawatt is enough electricity to power about 250 homes. Germany has the most installed wind energy capacity, followed by Spain, the United States, India, and Denmark. Development is also fast growing in France and China. Industry experts predict that if this pace of growth continues, by 2050 the answer to one third of the world's electricity needs will be found blowing in the wind.
Here then are the wind power pros and cons.
Pros
- Clean energy, no fuel to drill, frack, mine, transport or burn
- Renewable and sustainable
- Costs are relatively low and continue to decrease
- Abundant domestic supply (16X current electric demand!)
- The power is essentially free once the infrastructure is paid for.
- Low life cycle carbon footprint (Does not release carbon dioxide and other greenhouse gases that contribute to climate change)
- Can be used almost anywhere.
- Creates a steady demand for jobs, and this demand is expected to grow
ConsAt the end of 2011, the US had 46,919MW of installed wind capacity. This number is expected to grow rapidly, whether or not production tax credits (PTC) are renewed. There have been a number of recent mergers among wind developers as the industry consolidates. In summary, wind power, is not a perfect solution, but it is far better than just about anything else we have available at the moment. I would consider it a good long term transitional energy source over the next fifty to a hundred years. The other good thing about wind: unlike nuclear power, or tar sands oil, which will each leave a long term toxic legacy, when we are finally done with wind, we can simply take down the towers and allow nature to grow back in.
ARTICLE: Turning WIND into ELECTRICITY
The process of wind-produced electrical generation begins when the force of the wind pushes against the turbines’ blades, causing them to rotate, creating mechanical energy. Wind turbines operate on a simple principle. The energy in the wind turns two or three propeller-like blades around a rotor. The rotor is connected to the main shaft, which spins a generator to create electricity. Wind turbines are mounted on a tower to capture the most energy. At 100 feet (30 meters) or more above ground, they can take advantage of faster and less turbulent wind. Wind turbines can be used to produce electricity for a single home or building, or they can be connected to an electricity grid (shown here) for more widespread electricity distribution.
The spinning blades, attached to a hub and a low-speed shaft, turn along with the blades. The rotating low-speed shaft is connected to a gearbox that connects to a high-speed shaft on the opposite side of the gearbox. This high-speed shaft connects to an electrical generator that converts the mechanical energy from the rotation of the blades into electric energy. Spinning between 11 and 20 times per minute, each turbine can generate a maximum 1.5 megawatts of electricity -- enough to power, on average, more than 500 residential homes
Project WIND Discussion Forum
You are just about done with your project. But first you need to visit the online discussion forum and thoroughly answer one of the questions below in detail citing evidence. Remember, these questions should not be difficult because you have already done research. When you are finished, you are required to read and grade each response from every person in your lab group. Use the rubric below to guide you through the grading process. Remeber to make a claim and support that claim with evidence from the readings and research.
sentences that answer one of the required
questions above with correct spelling,
punctuation, & grammar
sentences that answer one of the required
questions above with mostly correct
spelling, punctuation, and grammar
complete sentences that answer one of
the required questions above
evidence were cited from the research
and readings.
evidence were cited from the research
and readings.
evidence were cited from the research
and readings.